Evacuated blood collection tubes are used for drawing blood from a patient for medical analysis. The tubes are sold evacuated. The patient's blood is communicated to the interior of a tube by inserting one end of a double-ended hypodermic needle into the patient's blood vessel and impaling the closure of the evacuated blood collection tube on the other end of the double-ended needle. The vacuum in the evacuated blood collection tube draws the blood (or more precisely, the blood pressure of the patient pushes the blood) through the needle into the evacuated blood collection tube, increasing the pressure within the tube and thus decreasing the pressure difference causing the blood to flow. The blood flow typically continues until the tube is removed from the needle or the pressure difference is too small to support flow.
Evacuated blood collection tubes should have a substantial shelf life to facilitate efficient and convenient distribution and storage of the tubes prior to use. For example, a one-year shelf life is desirable, and progressively longer shelf lives, such as 18 months, 24 months, or 36 months, are also desired in some instances. The tube desirably remains essentially fully evacuated, at least to the degree necessary to draw enough blood for analysis (a common standard is that the tube retains at least 90% of the original draw volume), for the full shelf life, with very few (optimally no) defective tubes being provided.
A defective tube is likely to cause the phlebotomist using the tube to fail to draw sufficient blood. The phlebotomist might then need to obtain and use one or more additional tubes to obtain an adequate blood sample.
Parenteral containers are designed to store pharmaceutical drugs for 2-3 years prior to use. These containers include: vials, cartridges, ampoules and pre-filled syringes. Prefilled syringes are commonly prepared and sold so the syringe does not need to be filled before use. The syringe can be prefilled with saline solution, a dye for injection, or a pharmaceutically active preparation, for some examples.
Commonly, the prefilled syringe is capped at the distal end, as with a cap, and is closed at the proximal end by its drawn plunger. The prefilled syringe can be wrapped in a sterile package before use. To use the prefilled syringe, the packaging and cap are removed, optionally a hypodermic needle or another delivery conduit is attached to the distal end of the barrel, the delivery conduit or syringe is moved to a use position (such as by inserting the hypodermic needle into a patient's blood vessel or into apparatus to be rinsed with the contents of the syringe), and the plunger is advanced in the barrel to inject the contents of the barrel.
One important consideration in manufacturing pre-filled syringes is that the contents of the syringe desirably will have a substantial shelf life, during which it is important to isolate the material filling the syringe from the barrel wall containing it, to avoid leaching material from the barrel into the prefilled contents or vice versa.
Since many of these vessels are inexpensive and used in large quantities, for certain applications it will be useful to reliably obtain the necessary shelf life without increasing the manufacturing cost to a prohibitive level. It is also desirable for certain applications to move away from glass vessels, which can break and are expensive to manufacture, in favor of plastic vessels which are rarely broken in normal use (and if broken do not form sharp shards from remnants of the vessel, like a glass tube would). Glass vessels have been favored because glass is more gas tight and inert to pre-filled contents than untreated plastics. Also, due to its traditional use, glass is well accepted, as it is known to be relatively innocuous when contacted with medical samples or pharmaceutical preparations and the like.
To increase the shelf life of such plastic vessels, a barrier coating may be applied to the vessel that is configured to inhibit at least oxygen from the ambient environment outside of the vessel from entering into the interior area of the vessel. Yet, permeation testing the integrity of such coatings is time consuming, taking as little as 24 hours to upwards of 21 days depending on the thickness and barrier properties of the container/coating system. For example, currently, testing of barrier coating integrity may involve the relatively long process of Oxygen Transmission Rate (OTR). The OTR is a measure of oxygen permeation. Typical instruments that perform OTR testing include Mocon and Oxysense. However, such testing may take 7-14 days before the results of the testing, and the integrity of the barrier coating of the particular sample being tested, can be assessed.
Additionally, due to the sensitive nature of testing barrier coating integrity, current testing methods encounter challenges relating to the interface between the measurement device and the vessel. Moreover, this interface may be configured in such a way that allows for the undesirable flow of gases outside of the vessel into the measuring device, which thereby contributes to the recorded gas flow measurements, and thereby adversely impacts the accuracy of the test results. In Mocon-Oxtran type permeation measurement, the test article must be destructively glued to a support fixture. In the Oxysense measurement, an oxygen-sensitive adhesive tab must be affixed to the inside wall of the article It would be desirable to enable measurement in a non-destructive mode.
A non-exhaustive list of patents of possible relevance includes U.S. Pat. Nos. 6,068,884 and 4,844,986 and U.S. Published Applications 20060046006 and 20040267194.